System and method for encoding high density geometric symbol set

ABSTRACT

A system and related techniques provide a platform for encoding high density geometric symbol sets, for example a triangular barcode-type of encoding which may be used to encode drivers&#39; licenses, biometric IDs, passports, or other transaction or identification media. According to embodiments of the invention in one regard, an inkjet, laser or other printer or output device may imprint a paper, plastic or other media with geometric symbols such as triangles in a defined array, to represent, for instance, name, address, or other identifying information, for instance such as digital facial photographs, iris or retinal scans, fingerprints, signatures, or other information. The geometric symbols may in one regard be arranged in a staggered format, separated in embodiments by a white space that may serve to reduce aliasing effects and other distortions. Because triangular symbols may in general be packed more closely together, and the number of distinct individual symbols may scale according to the range of color space employed for the symbol set, information densities high enough to satisfactorily encode biometric iris or retinal scans, digital facial photographs, or other identification or other information may be achieved. In embodiments, error correcting processing such as Reed-Solomon techniques may be employed to enhance scanning accuracy. In further embodiments, a reference palette may be embedded within the imprinted media, to provide a scale against which color fading or other distortion may be measured.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims benefit of priority toU.S. Patent application Ser. No. 11/022,863, filed on Dec. 28, 2004,which application is herein incorporated by reference. The subjectmatter of this application is also related to the subject matter of U.S.Provisional Application Ser. No. 60/583,571 filed Jun. 28, 2004 entitled“Ultra High Density Triangular Symbology Color Barcode Format”, whichapplication is assigned or obligation of assignment to the same entityas this application, from which application priority is claimed, andwhich application is incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

The invention relates to the field of symbol encoding in identificationsand transactional media, and more particularly to systems and methodsfor encoding bar code or other symbol sets in a color or grayscale spaceusing geometric symbol sets.

BACKGROUND OF THE INVENTION

Widespread bar code and other encoding technologies such as theuniversal product code (UPC) encoded on retail products, driver'slicenses and other commercial or identification media rely uponpredefined symbol sets defined for certain positions and sizes withinlabels and other materials. A traditional UPC, such as that illustratedin FIG. 1, and related codes however do not achieve a particularly highinformation density in terms of bits embedded per square inch, achievingon the order of 100-300 bits per square inch. This is due in one regardto the length and width of the code or symbol dimensions, which arecomparatively elongated. This is also due in another regard to thelimitation of the encoding technology to a black and white color scheme,in which the presence or absence of individual bits is represented by asingle black or white mark or symbol.

While this encoding scheme may enhance detection robustness because theseparation between coding symbols in terms of color space distance isgreatest, and permit the use of relatively low-cost or low-resolutionscanners because only black and white elements need to be discriminated,a price is paid in terms of information density. Simple black and whitebar codes have therefore as a rule proved insufficient or impracticalfor transaction or identification applications which demand greateroverall information content. Biometric IDs or medical insurance orinformation cards, for instance, may require the encoding of personalinformation such as an iris scan, a fingerprint image, a signatureimage, medical history, DNA or other information. In may applications,it is desirable to imprint that information on a comparatively compactplastic or paper card or other relatively inexpensive media, rather forinstance than resort to the much more expensive solution of a smart cardcontaining electronic intelligence. Drivers' licenses, passports orother ID media may likewise require a fairly high amount of informationcontent, including for example color digital face photographs.

As the pixel resolution of both printing devices such as laser printersand detection devices such as handheld scanners has increased, thepossibility has correspondingly arisen to enlarge both the symbol setand the color space in which bar and other symbol codes may beexpressed. Printing devices, and scanning or input devices in particularhave become available which are capable of close-contact optical orother scans at color depth resolutions of 8 bits (256 grayscale orcolor), 24, 32, 48 or greater bit depths. Enlarged color spaces combinedwith finer spatial resolution creates the potential for greaterinformation density on media.

Yet encoding for example a driver's license or biometric identificationcard at 32 bits per pixel at 200 lines per inch using square or blocksymbols may still result in scanning errors from discolored paper,pixelation, rotation or other misalignment or other problems in readingthe media and its symbols. Thus while information density may increasecompared to single-line two-color codes, accuracy or ultimate density incases may still be compromised or comparatively limited when usinggray-scale or color encoded in square or block symbol sets. Otherproblems in bar code and other encoding technology exist.

SUMMARY OF THE INVENTION

The invention overcoming these and other problems in the art relates inone regard to a system and method for encoding a high density geometricsymbol set, in which a triangular or other geometric barcode format isprovided using a comparatively densely packed symbol pattern that can inone regard achieve at least three times the density of industry standardsingle-line barcode formats such as PDF417/Datamatrix. According toembodiments of the invention in one regard, the encoded symbol set mayinclude built-in error detection or correction capabilities that can incases achieve at least over 1,100 bytes or 3,300 symbols per squareinch, even when printed on a conventional color inkjet printer.According to embodiments of the invention in one regard, triangular orother geometric symbol sets may be embedded with white spaces whichserve as a partition between adjacent symbols, enhancing detectionaccuracy. According to embodiments of the invention in another regard,the encoded symbol set may be expressed in gray-scale or color tones, at8, 24, 32, 48 or other bit depths, depending on application.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent application publication with color drawingswill be provided by the Office upon request and payment of the necessaryfee. The present invention is described in detail below with referenceto the attached drawing figures, wherein:

FIG. 1 illustrates a Universal Product Code (UPC), according to knowntechnology.

FIG. 2 illustrates a geometric symbol set for encoding data at highdensity, according to embodiments of the invention.

FIG. 3 illustrates an aspect of a geometric symbol set including whitespace separators, according to embodiments of the invention.

FIG. 4 illustrates certain rotation and scaling operations, according toembodiments of the invention.

FIG. 5 illustrates aliasing effects which may be manifested in certainimage capture operations.

FIG. 6 illustrates aliasing and pixelation effects which may bemanifested in certain image capture operations.

FIG. 7 illustrates aliasing and color blending effects which may bemanifested in certain image capture operations.

FIG. 8 illustrates aliasing and color blending effects which may bemanifested in certain image capture operations in another regard.

FIG. 9 illustrates aliasing effects which may be manifested in certainimage capture operations, according to embodiments of the inventionincluding triangular symbol sets.

FIG. 10 illustrates a geometric symbol set including a referencepalette, according to embodiments of the invention.

FIG. 11 illustrates data encoding including error correction encoding,according to embodiments of the invention.

FIG. 12 illustrates data encoding representations in a color space,according to embodiments of the invention.

FIG. 13 illustrates data encoding in media and certain decodingprocessing, according to embodiments of the invention.

FIG. 14 illustrates image capture processing of geometric symbolsincluding certain centering processing, according to embodiments of theinvention.

FIG. 15 illustrates an equation that may be used in certain symbolseparation and decoding processing, according to embodiments of theinvention.

FIG. 16 illustrates data encoding representations in a color space,according to embodiments of the invention in another regard.

FIG. 17 illustrates certain symbol decoding operations, according toembodiments of the invention.

FIG. 18 illustrates certain symbol decoding operations includingillumination compensation, according to embodiments of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 2 illustrates an encoded high density symbol set 102 according toembodiments of the invention in one regard. According to embodiments,each symbol in the symbol set 102 may be represented by a coloredgeometric figure, such as a triangle or other figure. Each symbol may berepresented by or encoded in a grayscale or color, such as a 2-bit (fourcolor), 3-bit (eight color), 4-bit (sixteen colors), 8-bit (256 color),24-bit (16.7 million colors), 32-bit (16.7 million colors plus alphachannel, or other colors), 48-bit or other color depth or color density.The issues and process for creating and decoding grayscale and colorcodes may in one regard be similar. For purposes of illustration, inembodiments a color representation of or format for symbol set 102 maygenerally be described.

According to embodiments of the invention in one regard, each individualsymbol within symbol set 102 may be or include a color or grayscaletriangle or other geometric shape or object that is distinctly spacedfrom its neighbors. According to embodiments of the invention in afurther regard, and as shown, at the end of the barcode a referencepalette 104 may be presented which displays a known reference range ofcolors that is being represented.

FIG. 3 illustrates a zoomed view of a portion of symbol set 102 shown inFIG. 2, including triangular symbols 106 and white spacing 108 betweenthose symbols. This symbol set 102 may for instance be scanned using ahigh-fidelity computer image capture device such as a flatbed scanner,business card scanner, CCD based camera or other close-contact or otherscanning or input device. In order to describe certain features of thesymbology and related encoding issues according to the invention, abrief outline or recapitulation of computer image capture and computergraphics and color theory is presented.

Computer image capture devices essentially capture an electronic oroptical impression of a real world picture or scene, and convert it intoa binary form that a computer and other digital equipment can process.Different types of digital representations of images, or bitmaps, withina computer are known. A computer capture device such as a digital stillcamera contains electronic sensors that are able to take an opticalimage viewed through a lens, and convert it into a known digitalrepresentation. An image may be decomposed into small single imagesquares or other elements called pixels which have a value that denotesthe pixel's color information or representation. In general the greaterthe number of pixels for a given scene, the better the clarity andreal-world representation of the image when expressed as a bitmap. Acolor pixel in a 24-bit depth bitmap may for example be represented as arange of Red 0-255, Green 0-255 and Blue 0-255 values. This RGB tripletcan then be rendered to a display or printing device which can producethe original color when viewed by the human eye. Images encoded indigital form may, for example, be stored in conventional file formatssuch as a Joint Photographic Experts Group (JPG), tagged image formatfile (TIFF), bitmap (BMP), graphic image format (GIF), portable networkgraphics (PNG) or other formats or files.

Once a bitmap representation of an image has been captured or received,a computer graphics application or other program may generally processthe image in some form in order to manipulate the captured information.In the case of embodiments of this invention, the barcode or otherencoding algorithm may rotate the captured image, and scale it to aknown working size, as needed. This allows precise examination anddecoding of the triangular symbols 106. FIG. 4 illustrates these steps,which results in a scaled image 110.

A persistent artifact in analog to digital conversion and computer imagemanipulation, such as rotation or scaling, is generally known asaliasing. “Aliasing” refers to a term describing an effect when analoginformation is converted to and represented in the digital domain. FIG.5 illustrates this type of effect. On the left is shown a hand-drawnline, and on the right is the line when captured and represented on acomputer. The digital conversion of the line maps the analog line onto agrid, essentially filling any grid square through which the line passes.Squares/pixels are either occupied (black) or empty (white). There is nohalf filling.

In order to better represent images within the computer, a mathematicaltechnique known as anti-aliasing can be applied to eliminate the jaggedappearance of approximated lines, and other distortions. Anti-aliasingtechniques in general attempt to smooth the line by filling in adjacentgrid squares/pixels with colors that are in between the two adjoiningcolors. FIG. 6 illustrates how blending of the colors may smooth theline or other object out. Image manipulation techniques, such asrotation, scaling and others may make use of anti-aliasing toeffectively transform the image so that it represents the original asclose as possible before the transformation, as opposed to exhibitingrough and jagged lines, edges and other features.

According to embodiments of the invention in one regard, and generallyspeaking, triangles as one candidate for a basic geometric object insymbol set 102 have certain advantageous properties when applied to abarcode or other format. First, they occupy less physical space whencompared to square symbols, since the triangle as an object has taperedsides. Second, triangles are less prone to the effects of anti-aliasing(which the scanning or other input system and subsequent imageprocessing will introduce), as they only present three straight-linedsides versus four for a square of block shape. With the addition ofwhite spacing 108 between symbols, the effects of anti-aliasing may inembodiments be further reduced. This yields more accurate color samplingthat is closer to the original, as compared with other methods.

FIG. 7 illustrates a magnified view of how square barcode cells may beaffected by the process of anti-aliasing. As can be seen, the centermagenta-colored cell is affected by its neighbors and its overall coloris skewed from its true color due to aliasing effects. FIG. 8 incontrast illustrates that the effects of color blending may in generalbe reduced with the addition of intervening white spaces between barcodesymbols. As can be seen, the cells are more true to the original color.However, adding a white space separator to a square barcode symbol setoccupies a significantly larger amount of surface area or physicalspace. Again, conservation of space and increased density are importantfor biometric ID and other comparatively information-rich applications.

FIG. 9 illustrates a triangular barcode symbology combined with theaddition of white spacing, according to embodiments of the invention. Inembodiments as illustrated, the appearance of white spacing 108 is notas pronounced as that in FIG. 8. The sample in FIG. 9 was for instancederived from a scan at a resolution of 3,300 symbols per square inch, sothat actual shape of the triangle is diluted, but the sampling of thedata values is accurate. The image on the right in FIG. 9 outlines thelogical locations of the triangle symbols in symbol set 102 in this typeof embodiment.

According to further embodiments of the invention, the symbol set 102may be provided with a reference palette 104 containing the unique setof colors that are being used to represent or color the symbols insymbol set 102. Printers from different manufacturers and differenttechnologies, such as inkjet, color laser or dye sublimation, producepaper output in differing color tones which may deviate from the colorvalue which has been sent in digital form to the printer. Moreover,paper or other printed or other media may age and alter color tone,size, shape, wrinkle or otherwise deform or distort. The ink, wax, dyeor other material used to imprint symbols in media may likewise fade,absorb moisture, smear or otherwise change or be altered over time. Duethese and other effects and artifacts, obtaining an exact comparisonbetween sampled color in a scan of symbol set 102 and an absolutedigital or reference palette or color may be unreliable.

However in embodiments, and as for example shown in FIG. 10, theaddition of the reference palette 104 within the structure of symbol set102 may supply a set of physical reference colors that is self-containedand permit a calibration or reference point, so that a scan andcomparison of symbol set 102 may produce highly accurate results. Thereference palette 104 may in one regard allows a comparison between thescanned or sampled symbol colors and a set of reference colors, so thatfor example color correction may be performed. Should there be instanceswhere the color palette is damaged or altered on the physical ID ormedia, the barcode or other reading intelligence may for example make aneducated estimate as to what they are likely to be as it averages ahistory of previously read barcode palette colors, or perform otherstatistical or other color correction. The RGB or other value of symbolsin symbol set 102 may therefore be adjusted to reflect the deviationfrom or remain consistent with reference palette 104, or be processed inother ways.

According to embodiments of the invention in another regard, the symbolset 102 of the invention may employ error corrective techniques toaddress media failure due to such things as paper blemishes, decodingmisinterpretations which may occur due to spurious artifacts from thescanning technology, color reference mismatches or other sources oferror or inaccuracy. The application of error correction techniques inembodiments may be desirable, since among other factors the colordetection tolerances in high density variants of the symbol set 102 maybe fairly strict. Therefore, according to embodiments of the invention,the decoding process of symbol set 102 may use error detecting orcorrecting algorithms such as Reed-Solomon error correcting codestogether with the Berlekamp decoding approach. Other error detection,correction or compensation techniques may likewise be used.

In the case of Reed-Solomon implementations, that class of codes wasdeveloped in 1960 by workers Irvine Reed and Gustave Solomon at M.I.T.,whose seminal article is Polynomial Codes over Certain Finite Fields,which publication is incorporated by reference herein. Elwyn Berlekampfrom University of California Berkeley devised an efficient decodingalgorithm for this class of codes, which in different implementationsforms the basis of today's error correction in technologies such ashard-disk drives, compact disks and other telecommunication and otherprotocols. The general approach to a Reed-Solomon implementation is toencode blocks of n-bit symbols, where the number of symbols encoded in ablock is m=2n−1, e.g.: a block operating on 8 bit symbols has 255 bytes.A variable amount of error corrections can be made per given block wheree<m. To encode a greater amount of data than the number of bytes in ablock, multiple symbols may be used. The data within each symbol may beencoded as points in a polynomial plotted over a finite field. Thecoefficients of the polynomial form the data in the block. The plotover-determines the coefficients, which can be recovered from theplotted points. In this way, a Reed-Solomon code can bridge a series oferrors in a block of data by recovering the coefficients of thepolynomial that drew the original curve. According to embodiments, theinvention may permit a scanning implementation to define how many errorscan be corrected per Reed-Solomon block and the composition of blocks ina given amount of data, for example, selecting multiple blocks or asingle large block.

In terms of generating the barcode or other data expression representedby symbol set 102, according to embodiments of the invention in oneregard an initial step of generating a CRC (Cyclic Redundancy Check) ofthe data to be stored in the symbol set 102 may be made, enabling alater scanning or verification phase to determine whether theencapsulated data has successfully been decoded. A CRC is a knownerror-detection scheme that uses parity bits generated from a polynomialand source data, and appends these bits to the original data itself. Theverification of a CRC may be done by recomputing the CRC parity bits onthe received data with the precomputed value to which it is appended.Should there be a discrepancy between the stored and recomputed valuesthe data may be assumed to be corrupt.

As a second encoding step, the physical dimensions of the barcode orother symbol set 102 may be determined in terms of number of symbols,width, height or other dimensions. In embodiments, a fixed width orheight is established and a remaining variable dimension may becomputed. The dimensions may be determined based on the number of colorsused (number of bits that can be represented per encoded symbol), thenumber of bytes of data that will be stored together with its CRC value,the additional Reed-Solomon redundancy overhead which can be computedwith the known size of the data, plus the number of symbols anyreference palette 104 may occupy. The number of rows of columns in thevariable dimension can then be determined. Should a non-integral size ofsymbols in the fixed dimension occur, the difference may be padded withalternating colors from the palette being employed. FIG. 11 illustrates,for visualization purposes only, how this may be physically laid out,according to embodiments of the invention.

A next step is to Reed-Solomon encode the data with its appended CRCvalue that will be stored in the barcode or other symbol set 102,combined with the digital values for the color space or palette and theextra-space padded symbols. Given the computation power generallyavailable even in typical devices such as Personal Digital Assistants,it may typically be possible to encode using one large Reed-Solomonblock, rather than having to encode multiple blocks. However, blockencoding choices may in one regard be left to implementation.

After any error detection or correction processing, the encoded binarydata may then be decomposed into the color values that the palette canrepresent by generating a color based on the number of bits a barcodecell's set of colors can represent. The binary data may be segmentedinto blocks of this number of bits and a color value is produced foreach segmented block. FIG. 12 illustrates this segmentation and colorassignment process, according to embodiments of the invention in oneregard. Following this, the generated colors may be assembled in thepredetermined barcode dimensions in order to produce a bitmap image ofsymbol set 102 or other encoded output. The barcode or other imagecontaining or expressing symbol set 102 may then be rendered or output,for example to a color printer or be embodied in an image or mediacontaining other print information.

According to embodiments of the invention in a further regard, thecorresponding processing of scanning, reading and decoding symbol set102 may include a first step of capturing the physical image of thesymbol set 102. Scanning or other input can be achieved in a variety ofways, for example by image capture via a computer flat-bed scanner, abusiness card reader scanner, digital camera, video camera, Web cam orother input device. The capture device may be configured to capture incolor or grayscale depending on the format of the barcode or othersymbol set 102, and the number of dots (or pixels) per inch that willform the image.

Generally the capture device may need to capture at least the number ofpixels per inch that the image was represented when being generated intobitmap form. For example, a symbol set 102 expressed in the form of abarcode of 38 triangles wide, each 7 pixels wide with one white spacepixel, forms a barcode 304 pixels wide that, when rendered to theprinter, forms a barcode that is approximately one inch wide. Thescanning process in such an illustrative case may need to be able tocapture an area of one inch in width into approximately 300 pixels.Should a lower density scan be used, then a lower image fidelity ofscanned image versus original will result and problems may arise whenprocessing and decoding the barcode or other symbol set 102.

Once the image of the symbol set 102, and in embodiments the rest of thedocument or media accompanying the symbol set 102, has been captured andstored in computer or other memory or storage so that decodingprocessing can occur, the next step is to identify where on the documentor media the symbol set 102 resides. Typically, existing barcode formatsuse specific alignment/location guides that are identifiable by theprocessing software. The symbol code 102 implemented according toembodiments of the invention is guide agnostic, given that it is a highfidelity barcode format and, based on the accompanying document's needs,tying to a specific alignment/location guide may not be visually orpractically appropriate. A variety of alignment/location approaches canbe used, as illustrated in FIG. 13, including, but not limited tophysical markers, document position specific, and advanced computervision pattern matching techniques, such as wavelet decomposition.

After the symbol code 102 has been identified and located within thescanned image, the decoding process may require the image of the symbolset 102 itself to be correctly rotated and scaled so that the colors ofeach triangle or other geometric symbol can be determined. Typically,the scanning process will produce an image that is not the exact scaleof the original media, and the placement of the document within thescanner is not aligned exactly to the horizontal plane. The scaling androtation process may be straightforwardly executed given the fourcorners of the extracted barcode image, using for example eithertrigonometric or vector based arithmetic techniques.

Once the final scaling and rotation of the symbol set 102 has beenfinalized, the sampling of the triangles or other constituent geometricsymbols can be done in a variety of ways. However, the inventor hasdetermined that one of the most accurate, or most accurate method,determined by trying different approaches without the reliance on errorcorrection, is an absolute position single pixel sampling, followed by acolor distancing comparison with the reference color values in thereference palette 104. FIG. 14 illustrates the bottom right-hand sectionof a processed scan of a barcode as one symbol set 102. The samplingpoints are denoted by the single white pixel as the sampling location.Note the reference palette at the bottom right-hand corner. Even if thepixels are sampled slightly offset from the center of the triangularsymbols 106 or other geometric symbols, there is sufficient colorinformation so that the reference color can be effectively determined.

According to embodiments in another regard, the next decoding phase isto map the sampled color values for the barcode cells to the referencepalette 104 so that the original colors can be determined and the databytes regenerated based on the bit pattern each cell represents. Amodified Euclidean distance function may compare the sample color witheach of the colors in reference palette 104. The smallest distancebetween the sample color and the palette color may consequently be theactual color that the cell or pixel represents. Given that the color ofa pixel in a bitmap may in embodiments for example be represented as arange of Red 0-255, Green 0-255 and Blue 0-255, and that this range doesnot map perfectly to how color is actually perceived by the sensors inhuman eyes, a well-known phenomenon, a weighted adjustment may need tobe made to reflect or compensate for this variation in perceived dynamicrange. FIG. 15 shows the weighted formula for color distancemeasurement, considering the emphasis the human eye places on certainranges of colors. Should the reference palette 104 be damaged, thedecoding software can fill in the gaps based on a history or previouslyscanned palette color values, a technique which has proven to beempirically reliable.

Reassembly of the actual data bytes from the read-out color values ofsymbol set 102 is in one regard essentially the reverse process of thebit segmentation in the code generation process. The bit pattern valuefor each cell color sequentially regenerates the data bytes. FIG. 16illustrates this process, in which set of three symbol color values aremapped to bytes. Reed-Solomon error correction may then be applied tothe resulting data bytes, to automatically detect and replace any badlyscanned or color matched data values. The CRC (Cyclic Redundancy Check)parity value may then be extracted from the barcode or other data blockof symbol set 102, a new CRC value may be recomputed on the remainingdata. Should the values not match, then the barcode or other symbol set102 may be determined to be either too badly damaged or the scanningprocess failed to faithfully reproduce the image of symbol set 102 fromthe scanned document or media. However, in embodiments the followingadaptive techniques may be applied to accommodate input difficultiessuch as badly calibrated scanners or damaged barcodes, should theinitial attempt at decoding the symbol set 102 fail.

There are at least two factors that may dictate the decode failure ofwhat should be a good or accurate barcode scan, namely alignmentfailures and color matching failures. Alignment failures can result froma poorly located barcode or other image from the original scanned image,so that therefore the sampling location is not directly within thecenter of the triangular or other symbols. In this case, an iterativeapproach may be used to offset the origin for all sampling points acrossthe barcode or other symbol set 102, for example by one pixel in eachdirection of the 8 magnetic compass points. FIG. 17 illustrates thiscorrection process on a single triangular symbol. The white pixel is theoriginal misaligned sample point. Any point clockwise between E and Swill yield a good color sample for the rest of the symbol set 102.

The second potential factor is a poorly calibrated scanner or wronglyset light settings, such as contrast or brightness. In this case, thecolors of the entire image of symbol set 102 may be adjusted inintensity, for example by changing the highlight component of the image.Highlight is a known image manipulation technique and is a function ofHighlight/Midtone/Shadow processing or settings. Adjusting the highlightcomponent has at least two beneficial effects. First, it lightens ordarkens the original image. Second, it tends to improve the colorseparation and intensity of colors across the barcode or other image.This process usually yields a correct result within approximately twoadjustments of highlight by −33 or other values, a process which FIG. 18illustrates. Other techniques for correcting illumination problems arepossible.

The foregoing description of the invention is illustrative, andmodifications in configuration and implementation will occur to personsskilled in the art. For instance, while the invention has generally beendescribed in terms of the extraction and processing of data encoded in asymbol set 102 embedded or printed on a drivers' license, passport,biometric ID or other transactional or identification media, inembodiments the scanned or otherwise acquired image data may be embeddedon other media or material, such as CDROM, fabric or textile material,analog or digital film, or other media, material or sources. Moreover,while the invention has in instances generally been described asinvolving encoding triangular symbols 106 in a barcode-type of format,in embodiments other coding formats, layouts or structures may be used.

Similarly, while the invention has in embodiments been described asemploying a single symbol set 102 in a given media or application, inembodiments more than one symbol set may 102 be encoded at one time onan identification or other media, for instance depending on or separatedby physical areas of the media or material. Other hardware, software orother resources described as singular may in embodiments be distributed,and similarly in embodiments resources described as distributed may becombined. The scope of the invention is accordingly intended to belimited only by the following claims.

1. A system for encoding a symbol set, comprising: an input interface toreceive information to be encoded in media; and an encoding engine, theencoding engine communicating with the input interface to receive theinformation and encode the information in a media as a set of coloredtriangular symbols including at least a first row of colored triangularsymbols pointed a first direction and a second row of colored triangularsymbols pointed a second direction that is opposite the first direction,wherein a white space separator is positioned between every two rows ofcolored triangular symbols and serves as a partition between the everytwo rows of colored triangular symbols.
 2. A system according to claim1, wherein the information comprises at least one of identificationinformation, transactional information and medical information.
 3. Asystem according to claim 2, wherein the information comprisesidentification information, and the identification information comprisesat least one of a facial image and biometric information.
 4. A systemaccording to claim 3, wherein the biometric information comprises atleast one of an iris scan, a thumbprint scan, a fingerprint scan and aDNA sample representation.
 5. A system according to claim 1, wherein theset of colored triangular symbols includes additional verificationinformation so that a content of the information encoded in the set ofcolored triangular symbols may be validated upon subsequent decoding ofthe set of colored triangular symbols using a cyclic redundancy check.6. A system according to claim 1, wherein the colored triangular symbolsinclude a subset of colored triangular symbols that form a referencecolor palette for verifying particular colors of individual coloredtriangular symbols in the set of colored triangular symbols.
 7. A methodfor encoding a symbol set, comprising: receiving, at a computing device,information to be encoded in media; encoding the information in a set ofcolored triangular symbols including at least a first row of coloredtriangular symbols pointed a first direction and a second row of coloredtriangular symbols pointed a second direction that is opposite the firstdirection in a color space in the media; and inserting a white spaceseparator between every two rows of the colored triangular symbols toserve as a partition between the every two rows of the coloredtriangular symbols.
 8. A method according to claim 7, wherein theinformation comprises at least one of identification information,transactional information and medical information.
 9. A method accordingto claim 8, wherein the information comprises identificationinformation, and the identification information comprises at least oneof a facial image and biometric information.
 10. A method according toclaim 9, wherein the biometric information comprises at least one of aniris scan, a thumbprint scan, a fingerprint scan and a DNA samplerepresentation.
 11. A method according to claim 7, wherein the colorspace comprises at least one of a set of grayscale values and a set ofcolor values.
 12. A method according to claim 7, wherein the set ofcolored triangular symbols includes additional verification informationso that a content of the information encoded in the set of coloredtriangular symbols may be validated upon subsequent decoding of the setof colored triangular symbols using a cyclic redundancy check.
 13. Amethod according to claim 7, wherein the colored triangular symbolsinclude a subset of colored triangular symbols that form a referencecolor palette for verifying particular colors of individual coloredtriangular symbols in the set of colored triangular symbols.
 14. Amethod according to claim 7, wherein the set of colored triangularsymbols further comprises a reference palette.
 15. One or morecomputer-readable media having computer-executable instructions embodiedthereon that, when executed, perform a method for encoding informationinto a set of encoded geometric symbols, the method comprising:receiving information to be encoded in a media; encoding the informationin the media using a set of colored triangular symbols including atleast a first row of colored triangular symbols pointed a firstdirection and a second row of colored triangular symbols pointed asecond direction that is opposite the first direction, wherein a whitespace separator is positioned between every two rows of the coloredtriangular symbols and serves as a partition between the every two rowsof the colored triangular symbols.
 16. The one or more computer-readablemedia of claim 15, wherein the information comprises at least one ofidentification information, transactional information and medicalinformation.
 17. The one or more computer-readable media of claim 16,wherein the information comprises identification information, and theidentification information comprises at least one of a facial image andbiometric information.
 18. The one or more computer-readable media ofclaim 17, wherein the biometric information comprises at least one of aniris scan, a thumbprint scan, a fingerprint scan and a DNA samplerepresentation.
 19. The one or more computer-readable media of claim 15,wherein the method further includes printing the set of coloredtriangular symbols onto the media.
 20. The one or more computer-readablemedia of claim 15, wherein the set of colored triangular symbolsincludes additional verification information so that a content of theinformation encoded in the set of colored triangular symbols may bevalidated upon subsequent decoding of the set of colored triangularsymbols using a cyclic redundancy check, and wherein the coloredtriangular symbols include a subset of colored triangular symbols thatform a reference color palette for verifying particular colors ofindividual colored triangular symbols in the set of colored triangularsymbols.